In recent years, a touch panel system, which accepts a user's instruction by detecting a position of an indicator (e.g., a user's finger or a stylus, the same applies hereinafter) that is in contact with or close to a detection surface of a touch panel, has been increasingly installed in a cell phone, a personal computer, a vending machine, and the like. Further, the touch panel system has recently come to be installed in a large-sized display device, a white board and the like, and there has thus been an increase in size of the touch panel.
In such a touch panel system, it is determined whether or not the indicator is in contact with or close to the detection surface based on an output signal outputted by the touch panel, but when some abnormality such as deformation occurs in the touch panel, the output signal varies due to the abnormality, and erroneous detection of the indicator thus occurs.
Therefore, for example, Patent Document 1 proposes a touch panel system in which, when the user presses the indicator to the detection surface of the touch panel more strongly than necessary, contact of the indicator is detected as distinguished from deflection that occurs in the touch panel, thereby suppressing erroneous detection of the indicator.